The prevalence of autism spectrum disorders (ASD) appears to be on the rise in developed countries and has become a serious public health concern. In most developing countries, however, the nature and prevalence of factors associated with ASDs are unknown. The long term goal of this planning project is to develop capacity for conducting large scale population-based ASD studies in Jamaica. First, the diagnostic criteria used in Jamaica and the United States will be compared. Then, questionnaires regarding the demographic and socioeconomic position, occupation, and drinking habits of each child's parents will be used, and information will be gathered about family history of developmental disorders, family size, birth order of the affected child, and whether the child is taking any medications. An age and sex matched case-control study, including a dietary questionnaire, will also be conducted to investigate whether environmental exposures to mercury, lead, arsenic, and cadmium play a role in autism. Blood and saliva samples will be collected to determine if any DNA polymorphisms that might affect interactions with heavy metals are present in children with ASD. New knowledge of potential environmental risk factors for ASD may arise from this research, thereby reducing physical, psychological, and economic burdens on the child, family, and society and helping parents make decisions about avoiding exposure to environmental contaminants.